00001 // 00002 // ******************************************************************** 00003 // * License and Disclaimer * 00004 // * * 00005 // * The Geant4 software is copyright of the Copyright Holders of * 00006 // * the Geant4 Collaboration. It is provided under the terms and * 00007 // * conditions of the Geant4 Software License, included in the file * 00008 // * LICENSE and available at http://cern.ch/geant4/license . These * 00009 // * include a list of copyright holders. * 00010 // * * 00011 // * Neither the authors of this software system, nor their employing * 00012 // * institutes,nor the agencies providing financial support for this * 00013 // * work make any representation or warranty, express or implied, * 00014 // * regarding this software system or assume any liability for its * 00015 // * use. Please see the license in the file LICENSE and URL above * 00016 // * for the full disclaimer and the limitation of liability. * 00017 // * * 00018 // * This code implementation is the result of the scientific and * 00019 // * technical work of the GEANT4 collaboration. * 00020 // * By using, copying, modifying or distributing the software (or * 00021 // * any work based on the software) you agree to acknowledge its * 00022 // * use in resulting scientific publications, and indicate your * 00023 // * acceptance of all terms of the Geant4 Software license. * 00024 // ******************************************************************** 00025 // 00026 // ------------------------------------------------------------ 00027 // GEANT 4 class header file 00028 // 00029 // History: 00030 // 17 August 2004 P.Gumplinger and T.MacPhail 00031 // samples Michel spectrum including 1st order 00032 // radiative corrections 00033 // Reference: Florian Scheck "Muon Physics", in Physics Reports 00034 // (Review Section of Physics Letters) 44, No. 4 (1978) 00035 // 187-248. North-Holland Publishing Company, Amsterdam 00036 // at page 210 cc. 00037 // 00038 // W.E. Fisher and F. Scheck, Nucl. Phys. B83 (1974) 25. 00039 // 00040 // ------------------------------------------------------------ 00041 #ifndef G4MuonDecayChannelWithSpin_hh 00042 #define G4MuonDecayChannelWithSpin_hh 1 00043 00044 #include <CLHEP/Units/PhysicalConstants.h> 00045 00046 #include "globals.hh" 00047 #include "G4ThreeVector.hh" 00048 #include "G4MuonDecayChannel.hh" 00049 00050 class G4MuonDecayChannelWithSpin : public G4MuonDecayChannel 00051 { 00052 // Class Decription 00053 // This class describes muon decay kinemtics. 00054 // This version assumes V-A coupling with 1st order radiative correctons, 00055 // the standard model Michel parameter values, but 00056 // gives incorrect energy spectrum for neutrinos 00057 00058 public: // With Description 00059 00060 //Constructors 00061 G4MuonDecayChannelWithSpin(const G4String& theParentName, 00062 G4double theBR); 00063 // Destructor 00064 virtual ~G4MuonDecayChannelWithSpin(); 00065 00066 protected: 00067 // Copy constructor and assignment operator 00068 G4MuonDecayChannelWithSpin(const G4MuonDecayChannelWithSpin &); 00069 G4MuonDecayChannelWithSpin & operator=(const G4MuonDecayChannelWithSpin &); 00070 00071 private: 00072 G4MuonDecayChannelWithSpin(); 00073 00074 public: // With Description 00075 00076 virtual G4DecayProducts *DecayIt(G4double); 00077 00078 void SetPolarization(G4ThreeVector); 00079 const G4ThreeVector& GetPolarization() const; 00080 00081 private: 00082 00083 G4ThreeVector parent_polarization; 00084 00085 // Radiative Correction Factors 00086 00087 G4double F_c(G4double x, G4double x0); 00088 G4double F_theta(G4double x, G4double x0); 00089 G4double R_c(G4double x); 00090 00091 G4double EMMU; 00092 G4double EMASS; 00093 00094 }; 00095 00096 inline void G4MuonDecayChannelWithSpin::SetPolarization(G4ThreeVector polar) 00097 { 00098 parent_polarization = polar; 00099 } 00100 00101 inline const G4ThreeVector& G4MuonDecayChannelWithSpin::GetPolarization() const 00102 { 00103 return parent_polarization; 00104 } 00105 00106 inline G4double G4MuonDecayChannelWithSpin::F_c(G4double x, G4double x0) 00107 { 00108 G4double omega = std::log(EMMU/EMASS); 00109 00110 G4double f_c; 00111 00112 f_c = (5.+17.*x-34.*x*x)*(omega+std::log(x))-22.*x+34.*x*x; 00113 f_c = (1.-x)/(3.*x*x)*f_c; 00114 f_c = (6.-4.*x)*R_c(x)+(6.-6.*x)*std::log(x) + f_c; 00115 f_c = (CLHEP::fine_structure_const/CLHEP::twopi) * (x*x-x0*x0) * f_c; 00116 00117 return f_c; 00118 } 00119 00120 inline G4double G4MuonDecayChannelWithSpin::F_theta(G4double x, G4double x0) 00121 { 00122 G4double omega = std::log(EMMU/EMASS); 00123 00124 G4double f_theta; 00125 00126 f_theta = (1.+x+34*x*x)*(omega+std::log(x))+3.-7.*x-32.*x*x; 00127 f_theta = f_theta + ((4.*(1.-x)*(1.-x))/x)*std::log(1.-x); 00128 f_theta = (1.-x)/(3.*x*x) * f_theta; 00129 f_theta = (2.-4.*x)*R_c(x)+(2.-6.*x)*std::log(x)-f_theta; 00130 f_theta = (CLHEP::fine_structure_const/CLHEP::twopi) * (x*x-x0*x0) * f_theta; 00131 00132 return f_theta; 00133 } 00134 00135 #endif